This invention relates to an artificial light source arrangement which is, in particular, of the type that the light emitted from a tubular light source whose horizontal light distribution curve takes on a substantial circle, such as fluorescent lamps or xenon lamps, is focused by a lens system, and the thus converged light is transmitted through a photoconductive cable to a place where lighting is required.
In general, electric bulbs may illuminate every place. With illumination in an explosive atmosphere or in the water, however, the electrical appliance to be applied for that purpose has to be of the explosion-proof or the waterproof type since there is a danger of explosion or short circuits. It is found, however, that currently available appliances of the explosion- or water-proof type are of a large size as well as a large weight and rather costly, and do not function well as far as explosion-proofness and waterproofness are concerned.